Today an item I was bidding for, was won at the amount of 14.37. The item number is 263717958017 and 14.37 is exactly the amount I put in gixen.
Looking at the bidding history, it seems my sniping bid haven't been placed at all.
Why is that and what may have happened?

The bidding history shows that the winning price was EUR 14.37 and that the winning bid was made at 11:34:02AM PDT, 5 seconds before the auction closed.

Looking at the automatic bid history, it appears that the bid increment applied to the winning bidder's bid was EUR 1.00, which means we don't know how much the winning bidder bid. All we know is that they bid at least EUR 14.37.

You say that (1) you had Gixen place a bid (snipe) of exactly EUR 14.37, and (2) Gixen reported that you won, but (3) you did not win and that your bid is not listed on the bidding history.

My guess is that your bid arrived moments later than the winning bidder's bid and was ultimately rejected by eBay; however, because your bid came within the same second as the winning bidder's, eBay's system indicated to Gixen that your bid was the winning bid (and sorted out the correct situation moments later).

Mario would have to check Gixen's logs to verify that. He'll probably do that when he sees this post, but you should feel free to contact him directly at the Gixen support address using the instructions found on the Contact page._________________John

If you don't know where you are going, you will wind up somewhere else.
--- Yogi Berra